Method and system to provide material removal and planarization employing a reactive pad

Abstract

Systems and methods to remove a first material located on a top surface of a workpiece are presented according to one aspect of the present invention. According to an exemplary method, the pad including a second material is positioned proximate to the workpiece so that a front surface of the pad contacts an exposed surface of the first material. The front surface of the pad is mechanically moved against the exposed surface of the first material to initiate a chemical reaction between the first material and the second material that yields a reaction product. The reaction product may be removed by using a chemical solution, by using the mechanical movement of the pad against the exposed surface of the first material or both.

What is claimed is:  
     
       1. A method of removing a first material located on a top surface of a workpiece using a pad positioned proximate to the workpiece, the method comprising: 
       positioning the pad proximate to the workpiece so that a front surface of the pad contacts an exposed surface of the first material, at least the front surface of the pad being made of a second material;  
       moving the front surface of the pad against the exposed surface of the first material to initiate a chemical reaction between the first material and the second material, the chemical reaction yielding a reaction product; and  
       removing the reaction product using a chemical solution, the reaction product being soluble into the chemical solution, and the first material and the second material not being substantially soluble into the chemical solution.  
     
     
       2. The method according to  claim 1 , further comprising: 
       rotating, vertically moving, and laterally moving the pad relative to the workpiece using a shaft coupled to the pad.  
     
     
       3. The method according to  claim 2 , wherein the pad is wholly comprised of the second material. 
     
     
       4. The method according to  claim 2 , wherein the second material is stored within the pad. 
     
     
       5. A method of removing a first material located on a top surface of a workpiece using a pad positioned proximate to the workpiece, the method comprising: 
       positioning the pad proximate to the workpiece so that a front surface of the pad contacts an exposed surface of the first material, at least the front surface of the pad being made of a second material;  
       moving the front surface of the pad against the exposed surface of the first material to initiate a chemical reaction between the first material and the second material, the chemical reaction yielding a reaction product; and  
       removing the reaction product using the movement of the front surface of the pad, wherein moving the front surface of the pad against the exposed surface of the first material is not sufficient to remove the first material but is sufficient to remove the reaction product.  
     
     
       6. A method of removing a first material located on a top surface of a workpiece using a pad positioned proximate to the workpiece, the method comprising: 
       positioning the pad proximate to the workpiece so that a front surface of the pad contacts an exposed surface of the first material, at least the front surface of the pad being made of a second material;  
       moving the front surface of the pad against the exposed surface of the first material to initiate a chemical reaction between the first material and the second material, the chemical reaction yielding a reaction product; and  
       removing the reaction product using a chemical solution and the movement of the front surface of the pad, the reaction product being soluble into the chemical solution, the first material and the second material not being substantially soluble into the chemical solution, wherein moving the front surface of the pad against the exposed surface of the first material is not sufficient to remove the first material but is sufficient to remove the reaction product.  
     
     
       7. A method of removing a first material located on a top surface of a workpiece using a pad positioned proximate to the workpiece, the method comprising: 
       positioning the pad proximate to the workpiece so that a front surface of the pad is sufficiently close to an exposed surface of the first material but does not touch the exposed surface of the first material, the pad comprising a second material;  
       moving the pad with respect to the workpiece to initiate a chemical reaction between the first material and the second material, the chemical reaction yielding a reaction product; and  
       removing the reaction product using a chemical solution, the reaction product being soluble into the chemical solution, and the first material not being substantially soluble into the chemical solution.  
     
     
       8. The method according to  claim 7 , wherein the second material is not substantially soluble into the chemical solution. 
     
     
       9. The method according to  claim 7 , wherein the reaction product is removed predominantly using the chemical solution and not by using the movement of the pad so that a removal rate of the first material is independent of a pressure applied between the pad and the workpiece. 
     
     
       10. A method of removing a first material located on a top surface of a workpiece using a pad positioned proximate to the workpiece, the method comprising: 
       positioning the pad proximate to the workpiece so that a front surface of the pad is sufficiently close to an exposed surface of the first material and contacts the exposed surface of the first material so that the pad is subjected to minimal deformation with respect to a thickness of the pad, at least the front surface of the pad being made of a second material;  
       moving the pad against the exposed surface of the first material and with respect to the workpiece to initiate a chemical reaction between the first material and the second material, the chemical reaction yielding a reaction product; and  
       removing the reaction product using a chemical solution and the movement of the pad, the reaction product being soluble into the chemical solution, and the first material not being substantially soluble into the chemical solution.  
     
     
       11. The method according to  claim 10 , wherein the second material is not substantially soluble into the chemical solution. 
     
     
       12. The method according to  claim 10 , further comprising: 
       removing the first material using the movement of the pad.  
     
     
       13. The method according to  claim 12 , wherein a removal rate of the first material is nearly independent of a pressure applied between the pad and the workpiece. 
     
     
       14. The method according to  claim 13 , wherein the step of positioning subjects the pad to minimal deformation with respect to a thickness of the pad. 
     
     
       15. A method of removing a first material located on a top surface of a workpiece using a combination pad positioned proximate to the workpiece, the method comprising: 
       positioning the combination pad proximate to the workpiece so that a front surface of the combination pad contacts an exposed surface of the first material, the combination pad comprising a combination of a reactive pad material and a mechanical pad material;  
       moving the front surface of the combination pad against the exposed surface of the first material to initiate a chemical reaction between the first material and the reactive pad material, the chemical reaction yielding a reaction product;  
       removing the reaction product using a chemical solution, the reaction product being soluble into the chemical solution, and the first material not being substantially soluble into the chemical solution; and  
       removing the first material and the reaction product using the mechanical pad material of the combination pad during the movement of the front surface of the combination pad.  
     
     
       16. The method according to  claim 15 , wherein the reactive pad material is not substantially soluble into the chemical solution. 
     
     
       17. A method of removing a first material located on a top surface of a workpiece using a first pad having a first front surface and a second pad having a second front surface, the first pad positioned adjacent to, but separately from, the second pad, the method comprising: 
       positioning the first pad and the second pad proximate to the workpiece so that at least one of the first surface and the second surface contact an exposed surface of the first material, the first pad comprising a reactive pad material and the second pad comprising a mechanical pad material;  
       moving the first front surface of the first pad against the exposed surface of the first material to initiate a chemical reaction between the first material and the reactive pad material of the first pad, the chemical reaction yielding a reaction product; and  
       removing the reaction product using a chemical solution, the reaction product being soluble into the chemical solution, and the first material not being substantially soluble into the chemical solution.  
     
     
       18. The method according to  claim 17 , wherein the reactive pad material of the first pad is not substantially soluble into the chemical solution. 
     
     
       19. The method according to  claim 18 , further comprising: 
       moving the second front surface of the second pad against the exposed surface of the first material.  
     
     
       20. The method according to  claim 19 , further comprising: 
       removing the first material using the mechanical pad material of the second pad during the movement of the second front surface of the second pad.